When emergency personnel such as firemen enter an emergency location, they are often faced with dangerous conditions, such as open flames, smoke, toxic gases, and the like. which may, on occasion, lead to incapacity of one or more of the emergency workers or people. In the case of a fire location, the incapacity of a person in the region of the fire may be life-threatening. Incapacity of a person in such an emergency location is often accompanied by unconsciousness, and therefore by an inability of the worker to either extricate himself from the location, or even to communicate his plight to rescue workers. Even if incapacity does not result in unconsciousness, the emergency worker may be disoriented by loss of sensory information due in part to the environment, which may be dark, smoke-filled, and subject to falling debris and open flame, and also due in part to the nature of the emergency equipment which is used, which may include heavy air tanks, respirators or masks which prevent effective use of the sense of smell, goggles which, together with environmental smoke or haze, and flares of flame, impair eyesight, and gloves which reduce the sensation of touch.
If the emergency worker who is incapacitated does not respond to communications, his incapacity may be realized early by other workers at the site, or his incapacity may be inferred by his failure to exit the site after a period of time. In either case, the incapacitated worker must be found and extricated from the emergency area. The same effects which caused the initial disorientation or incapacity of the worker being sought also apply to those seeking his rescue. It is vital, for the safety of the incapacitated worker and of his rescuers, that he be located promptly. It has been found that focussed Xenon-halogen flashlights can penetrate a reasonable distance in a smoky atmosphere, but reflections from smoke particles create a bloom which results in partially blinding the user, as the use of high beams in fog tends to reduce the contrast of the scene relative to low beams. Recovery of the dark-adapted eye from an exposure to bright white light has been shown to take up to several minutes.